feat: Add more math functions (#1091)

Author: rohitjangid

doc/_stdlib_gen/stdlib-content.jsonnet

@@ -110,12 +110,20 @@ local html = import 'html.libsonnet';
               <ul><code>std.acos(x)</code></ul>
               <ul><code>std.atan(x)</code></ul>
               <ul><code>std.round(x)</code></ul>
+              <ul><code>std.isEven(x)</code></ul>
+              <ul><code>std.isOdd(x)</code></ul>
+              <ul><code>std.isInteger(x)</code></ul>
+              <ul><code>std.isDecimal(x)</code></ul>
           </ul>
           <p>
               The function <code>std.mod(a, b)</code> is what the % operator is desugared to. It performs
               modulo arithmetic if the left hand side is a number, or if the left hand side is a string,
               it does Python-style string formatting with <code>std.format()</code>.
           </p>
+          <p>
+              The functions <code>std.isEven(x)</code> and <code>std.isOdd(x)</code> use integral part of a
+              floating number to test for even or odd.
+          </p>
         |||,
       ],
       fields: [

stdlib/std.jsonnet

@@ -1752,6 +1752,11 @@ limitations under the License.
   contains(arr, elem):: std.any([e == elem for e in arr]),
 
   equalsIgnoreCase(str1, str2):: std.asciiLower(str1) == std.asciiLower(str2),
+
+  isEven(x):: std.round(x) % 2 == 0,
+  isOdd(x):: std.round(x) % 2 != 0,
+  isInteger(x):: std.round(x) == x,
+  isDecimal(x):: std.round(x) != x,
 
   removeAt(arr, at):: [
     arr[i],

test_suite/stdlib.jsonnet

@@ -1579,6 +1579,15 @@ std.assertEqual(std.contains([1, 2, 3], 'foo'), false) &&
 std.assertEqual(std.equalsIgnoreCase('foo', 'FOO'), true) &&
 std.assertEqual(std.equalsIgnoreCase('foo', 'bar'), false) &&
 
+std.assertEqual(std.isEven(10), true) &&
+std.assertEqual(std.isEven(5), false) &&
+std.assertEqual(std.isOdd(5), true) &&
+std.assertEqual(std.isOdd(10), false) &&
+std.assertEqual(std.isInteger(1), true) &&
+std.assertEqual(std.isInteger(1.1), false) &&
+std.assertEqual(std.isDecimal(1.1), true) &&
+std.assertEqual(std.isDecimal(1), false) &&
+
 std.assertEqual(std.remove([1, 2, 3], 2), [1, 3]) &&
 std.assertEqual(std.removeAt([1, 2, 3], 1), [1, 3]) &&